Erection procedure for vertical shaft air preheaters

ABSTRACT

The method of manufacturing a rotor for a vertical shaft air preheater that rotates about a vertical axis between streams of hot gas and cool air. The rotor comprises a series of independent compartments that each contain a mass of heat absorbent element. The rotor is constructed by simultaneously securing to a rotor post two similar sector shaped compartments disposed at 180* to each other about the rotor post and by continuing to attach additional pairs of similar sector shaped compartments to opposite sides of thr rotor post until the compartments define a rotor. During construction there is at all times a substantially balanced assembly. The compartments are pivotally attached to the rotor post and joined together at their outer extremeties to form a composite assembly that extends around the rotor post.

[ 1 Sept. 23, 1975 ERECTION PROCEDURE FOR VERTICAL SHAFT AIR PREHEATERS [75] Inventor: Robert Emmett Mahoney,

Wellsville, NY.

[73] Assignee: The Air Preheater Company, Inc., Wellsville, NY.

22 Filed: Sept. 12, 1974 21 Appl. No.: 505,421

[52] US. Cl 29/l57.3 R; 29/429; 29/469;

113/118 R; 165/9 [51] Int. Cl. B21D 53/02; B23P 15/26 [58] Field of Search 29/157.3 R, 157.3 D,

156.8 CF, 29/429, 469; 113/118 R, 118 D; 165/9,1O

Kurschner et a1 29/157.3 R

FOREIGN PATENTS OR APPLICATIONS Japan 29/l56.8 CF

Primary ExaminerC. W. Lanham Assistant Examiner-D. C. Reiley, I11 Attorney, Agent, or Firm-Wayne H. Lang [57] ABSTRACT The method of manufacturing a rotor for a vertical shaft air preheater that rotates about a vertical axis between streams of hot gas and cool air. The rotor comprises a series of independent compartments that each contain a mass of heat absorbent element. The rotor is constructed by simultaneously securing to a rotor post two similar sector shaped compartments disposed at 180 to each other about the rotor post and by continuing to attach additional pairs of similar sector shaped compartments to opposite sides of thr rotor post until the compartments define a rotor. During construction there is at all times a substantially balanced assembly. The compartments are pivotally attached to the rotor post and joined together at their outer extremetiesto form a composite assembly that extends around the rotor post.

6 Claims, 2 Drawing Figures ERECTION PROCEDURE FOR VERTICAL SHAFT AIR PREHEATERS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a rotary regenerative air preheater and has particular relation to an arrangement by which compartments or baskets that carry a mass of heat absorbent element are assembled around a rotary shaft that in turn is disposed about a vertical axis. The rotary shaft and the assembly of element baskets are combined into a unit that operates as an integral body but one in which the several parts thereof are independent and free to thermally expand and contract.

2. Description of Prior Art Rotary regenerative air preheaters are customarily made of individual parts that are assembled and then connected together by a system of welded joints in the manner defined by US. Pat. No. 3,267,562 of Chiang. An air preheater constructed in this manner is initially strong, but when subjected to repeated heating and cooling as may attend normal service operations, a differential of expansion occurs between the several parts and a substantial stress is accordingly concentrated in the welded joints therebetween with a resulting crack ing or breaking of the welded joints so that the serviceability of the air preheater is materially impaired.

In US. Pat. No. 3,710,850 of Kurschner, et al, a rotary regenerative heat exchanger is disclosed wherein independent but similar compartments of heat absorbent element are pivotally attached to a central rotor post that is supported on bearings at the ends thereof for rotation about a horizontal axis. While suitable for horizontal" type air preheaters that inherently assume a state of balance during construction thereof, such arrangements have never proved practical for air preheaters of the vertical type because the great weight of the constituent elements causes problems of rotor imbalance when during assembly the elements thereof are progressively attached to a central rotor post.

SUMMARY OF THE INVENTION In accordance with the present invention, 1 therefore provide a procedure whereby an air preheater comprising a series of similar sector shaped compartments may be assembled about the periphery of a vertically disposed central rotor post. The assembly procedure defined is adapted to permit the gradual assembly of heavy compartments without attendant problems of imbalance, and it is moreover designed to provide a vertical shafted composite rotor of integral parts that are pivotally joined together whereby they are free to expand and contract as dictated by thermal change and not subject to cracking and breaking of welds as associated with continuous expansion and contraction of elements that are joined together by welding.

BRIEF DESCRIPTION OF THE DRAWING The nature of the invention and its novel features will be more fully understood from the following description and shown in the accompanying drawings in which:

FIG. I is a sectional view of an air preheater made generally according to the present invention, and

FIG. 2 is a preferred embodiment of the invention as contained in a perspective view of the apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT The arrangement of the drawing shows a rotary regenerative heat exchanger witha vertically disposed rotor post 12 having a support bearing 14 at the lower end thereof and a guide bearing 16 at the upper end thereof on transverse support structure 35. The rotor assembly comprising a series of sector shaped compartments 26 is pivotally attached to the rotor post at upper and lower connections 30 and 33, and it is rotated about its vertical axis by a drive motor 18 that is connected through suitable reduction gearing 22 to the rotor post 12. A mass of permeable heat absorbent material 24 contained in the independent sector shaped compartments 26 is adapted to absorb heat from hot fluid and then give it up to cooler fluid as it flows therethrough. i

The compartments 26 are open at opposite ends thereof to permit the countercurrent flow of hot gas and cooler air and they are secured to the'rotor post 12 by pivotal linkage 30 33 which permits limited relative movement between the compartments and the rotor post 12 as may be brought about by thermal expansion and contraction.

The assembled compartments are surrounded by a rotor housing 32 having openings 36, 38, 42 and 44 opposite ends of the rotor for the inlet and outlet of the hot gas and cooler air.

To preclude the leakage of fluid through the space between the rotor and the rotor housing, radial sealing means 45 in the form of elongate leaves are inserted be: tween the end edges of the composite rotor compartments and held by bolts 49 while circumferential seals 47 at the peripheral edge of the rotor are adapted to bridge the space between the rotor and the surrounding rotor housing in accordance with standard practice.

Pivotal couplings 30 33 are attached independently to rotor post 12 to support each compartment in a manner that permits a limited amount of relative movement therebetween as is necessary to accommodate normal variations. The radial outer ends of the sectorial rotor compartments 26 are bolted together as at 52 to comprise an integral rotor mass that extends as an annular body around the rotor post.

Inasmuch as the rotor is built up progressively from independent modules or components that may themselves weigh up to 50 tons, a great imbalance of forces is experienced during assembly thereof whenever the construction procedure reaches a stage that requires attaching one or more units to the side of an already balanced rotor post. This invention accordingly defines an erection procedure that is adapted to minimize the imbalance of forces that will accompany the assembly of a modular design air preheater wherein independent rotor compartments are added progressively to a vertical rotor post. i

In accordance with this invention, a support bearing 14 is first connected to suitable structure such as a horizontal beam 10 capable of supporting the entire air preheater. One end of the rotor post 12 is vertically supported in the support bearing 14 and the opposite end of the vertically disposed rotor post is supported against lateral movement by a guide bearing 16 that is itself carried by a support beam or other structure 35 having a predetermined strength sufficient to preclude lateral movement thereof when loaded unevenly as by an element compartment 26 that may be temporarily positioned at one side of the rotor postv A rotor compartment 26 containing a mass of heat absorbent element 24 is then moved by an overhead hoist or other lifting means shown schematically at 55A into position laterally adjacent the rotor post 12 and is attahced thereto by pins 56 in accordance with standard porcedure. Without releasing its support of the first compartment, a second hoist 55B is adapted to lift a second compartment 26 to the rotor post at a point that is removed 180 from the first compartment. Both compartments 26 are attached to the rotor post by means of a standard pivotal attachment that includes a lower compression fitting 33 and the upper tension fitting 30. Inasmuch as the rotor compartments supported on opposite sides of the rotor post together with the central rotor post now present at a symmetrical assembly, such assembly provides a balanced load bearing vertically downward upon the support bearing 14 with no lateral forces being exerted upon the axially spaced guide bearing. Therefore both hoists 55 may be immediately removed and made ready to simultaneously lift another pair of element compartments into position at opposite sides of the rotor post.

Additional rotor compartments 26 are then lifted into position adjacent opposite compartments 26 that are already attached to the rotor post, and they are pivotally secured in the same manner as those already attached thereto so that there is at all times a balanced assembly. After the compartments 26 are pivotally connected to the rotor post, the hoists 55A and 55B are removed and the compartments are secured loosely by bolts 52 to an adjacent basket so they are free to adjust themselves to a slight repositioning of the rotor compartments.

Subsequent compartments 26 are progressively at tached to opposite sides of the rotor post 12 and to adjacent compartments until an annular assembly of compartments extends completely around the rotor post, all of which are held to the rotor post by a pivotal connection 56 and to one another by bolts 52.

After the rotor has been completely assembled each loose connection 52 between baskets is progressively tightened so that the rotor assumes a permanent annular configuration concentric with the rotor post and having radial sealing means 45 positioned between edges of adjacent baskets wherein circumferential seals 47 are adapted to bridge the spacing between the rotor and a surrounding rotor housing.

Instead of hoists 55 being used to hold the compartments 26 until pairs thereof are secured to opposite sides of the rotor post, the compartments may be lifted into position adjacent the rotor post and supported temporarily on compression type supports on the underside thereof until the compartments are secured to the rotor post. When a pair of compartments are secured opposite sides of the rotor post, the supports therefor may be removed and replaced in such a position that additional compartments may be supported thereby until the rotor is complete.

This and other analagous steps may be utilized without departing from the spirit of the invention. It is therefore intended that other modifications and variations may be made without departing from the intent of the invention and that the details of the invention are to be limited only by the scope of the appended claims.

I claim:

1. The method of manufacturing a rotor for a vertical shaft rotary regenerative air preheater comprising the steps of supporting one end of a vertical rotor post in a rotatable support bearing, positioning the opposite end of said rotor post in a guide bearing that precludes lateral movement of the rotor post, positioning a sector shaped element compartment radially adjacent the rotor post and attaching it thereto while substantially simultaneously attaching a similar element compartment to the rotor post removed from the first rotor compartment so that there is at all times a substantially balanced assembly, and continuing to attach similar sector shaped compartments to opposite sides of said rotor post until the combined assembly of compartments comprises a composite rotor that extends concentrically around the rotor post.

2. The method of manufacturing a rotor for a rotary regenerative air preheater as defined in claim 1 further including the step of pivotally attaching each compartment to the rotor post.

3. The method of manufacturing a rotor for a rotary regenerative air preheater as defined in claim 1 wherein two sector shaped compartments are positioned simultaneously at alternate sides of the rotor post after a single compartment has been initially attached to each of opposite sides of the rotor post.

4. The method of manufacturing a rotor for a rotary regenerative air preheater as defined in claim 1 including the step of temporarily supporting each compartment on compression type supports on the underside thereof until a similar compartment is attached to the rotor post in a position removed substantionally 180 therefrom.

5. The method of manufacturing a rotor for a regenerative air preheater as defined in claim 4 including the step of removing the means supporting diametrically opposite compartments from the rotor post before attaching additional compartments thereto.

6. The method of manufacturing a rotor for a r'egenerative air preheater as defined in claim 1 including the step of providing means supporting each rotor compartment adjacent the rotor post with its radius substantially normal to the axis of the rotor post. 

1. The method of manufacturing a rotor for a vertical shaft rotary regenerative air preheater comprising the steps of supporting one end of a vertical rotor post in a rotatable support bearing, positioning the opposite end of said rotor post in a guide bearing that precludes lateral movement of the rotor post, positioning a sector shaped element compartment radially adjacent the rotor post and attaching it thereto while substantially simultaneously attaching a similar element compartment to the rotor post 180* removed from the first rotor compartment So that there is at all times a substantially balanced assembly, and continuing to attach similar sector shaped compartments to opposite sides of said rotor post until the combined assembly of compartments comprises a composite rotor that extends concentrically around the rotor post.
 2. The method of manufacturing a rotor for a rotary regenerative air preheater as defined in claim 1 further including the step of pivotally attaching each compartment to the rotor post.
 3. The method of manufacturing a rotor for a rotary regenerative air preheater as defined in claim 1 wherein two sector shaped compartments are positioned simultaneously at alternate sides of the rotor post after a single compartment has been initially attached to each of opposite sides of the rotor post.
 4. The method of manufacturing a rotor for a rotary regenerative air preheater as defined in claim 1 including the step of temporarily supporting each compartment on compression type supports on the underside thereof until a similar compartment is attached to the rotor post in a position removed substantionally 180* therefrom.
 5. The method of manufacturing a rotor for a regenerative air preheater as defined in claim 4 including the step of removing the means supporting diametrically opposite compartments from the rotor post before attaching additional compartments thereto.
 6. The method of manufacturing a rotor for a regenerative air preheater as defined in claim 1 including the step of providing means supporting each rotor compartment adjacent the rotor post with its radius substantially normal to the axis of the rotor post. 